A headrest of this type is described, for example in DE-OS 38 17 147. The underside of the protective covering of that headrest has a seam along its entire length, through which the closed frame can be inserted in the protective covering. Closing the relatively long seam requires a good deal of unwanted work. In addition, most people seem to feel that this kind of seam is rather unattractive.
The objective of the invention is to design a headrest of the type specified above in such a way that its protective covering needs only a very small, seam-closed opening for inserting the frame. An additional objective of the invention is the development of a method for producing such a headrest.
The invention achieves the first objective by providing a means of releasable attachment of the crossbar to the arms of the U-shaped support piece.
This design makes it possible to insert the U-shaped support piece into the protective covering with the crossbar detached. This is accomplished by a threading procedure. Therefore, the opening in the protective covering does not need to be any larger than the cross section of the support piece. The crossbar can then be inserted through the same opening and attached to the arms of the support piece, so that the frame becomes closed only after it is inside the protective covering. Due to this design of the invention, only a very small opening is needed in the underside of the protective covering. This improves the appearance of the headrest compared to the known headrest.
In accordance with an advantageous design of the invention, each arm of the U-shaped support piece has a crossbar mounting receptacle that faces downwards. The ends of the crossbar are inserted into these mounts. This makes it especially easy to attach the crossbar to the arms of the U-shaped support piece inside the protective covering.
To prevent unintentional detachment of the crossbar from the support piece, the crossbar mounting receptacle and/or the ends of the crossbar are equipped with locking mechanisms that hold the inserted crossbar securely in place.
Headrests are usually designed to have limited swiveling movement relative to their stay bars. In accordance with an especially advantageous design of the invention, this can be accomplished by mounting each of the stay bars inside the U-shaped support piece in a swivel, which swivels in a bearing. The bearing consists of two bearing shells connected by a film hinge. In the assembled state of the bearing, the bearing shells are folded together.
This bearing design, with two bearing shells connected by a film hinge, is already known in headrests design, as DE-AS 24 05 774 shows. However, in this design, a horizontal detachable crossbar connecting piece, located between the stay bar, forms the swivel axis of the headrest. Therefore, the bearing shells need to be held only by this connecting piece.
The swivels are especially simply designed when they are formed by a cylindrical disk with a radial borehole for receiving a stay bar.
The headrest is held very stably and with strong resistance to bending when, in accordance with another design of the invention, the stay bars pass through the swivel and, above the swivel, extend into a cross-sectionally triangular space inside the U-shaped support piece.
By providing slideable mounting of the stay bars in the swivels, the height of the headrest can be adjusted by moving the stay bars in or out.
If the bearings and U-shaped support piece are designed as one piece, they can be inexpensively produced as a single die-cast part.
The headrest has an especially attractive appearance if the protective covering has an opening that is only as large as the cross section of the U-shaped support piece. The support piece and the crossbar are threaded through the opening, and the opening is sealed before the covering is filled with foam.
The second objective of the invention, i.e., the development of a method for producing a headrest of the type described above, is accomplished in accordance with the invention by first threading a U-shaped support piece through an opening in the protective covering, then inserting a crossbar and locking it in place in the arms of the support piece, and finally, filling the space between the frame (consisting of the U-shaped support piece and the crossbar) and the protective covering with foam.
This method is very simple and therefore inexpensive to perform and produces a headrest that has only a very small seam on its underside for sealing the opening necessary for inserting the disassembled frame.